The physics core will serve as a central resource for all physics, computers and dosimetry related services. In the area of computers it will provide hardware and software support for all the Research projects and Cores of the tomotherapy based optimization routines, dose computation, treatment delivery, uncertainty minimization and major tasks would be to organize and apply an integrated database for all aspects of imaging, treatment planning, helical dose delivery and dose reconstruction and verification processes being developed and implemented by tomotherapy. The computation support would also provide integrated information on all treatment protocol related data. A routine quality assurance methodology will be implemented for all computational services. The physics dosimetry component of this core will address specific needs of optimized treatment planning, tomotherapy accelerator system dose output calibration, and safe adaptive delivery of treatments. It will provide tools for necessary immobilization and positioning as well as for monitoring variations of positron and motion. Of importance in this regard is the implementation of a stringent quality assurance for all tomotherapy processes. This will involve the use of a large number of analytical, ionographic and radiodichromic films, thermoluminescent and gel dosimeters. Monte Carlo simulation will be performed as needed.